Latch mechanisms have been used to releasably secure a seat back against a seat base. For example, commonly owned U.S. Pat. No. 5,414,897 to Loewe teaches the use of a latch plate having a pocket, and a tooth with a latching face, where the tooth has a first radius of curvature about a center lying on a first axis. A latch is releasably engageable with the latch plate, and has a nose with a latching face. The nose has a second radius of curvature about a second center lying on a second axis, and the latching face of the nose mates with the latching face of the tooth in a latching position. The latch further comprises a heel which contacts the pocket upon movement of the latch into the latching position. In this way, the latch fits snugly into the latch plate. As the system wears the latch fits ever further against the latching face, maintaining tight contact and preventing chucking, that is, a loose fit between members that allows relative wobbling in response to vibrational forces. Although this design works well in securing a pivotable member relative a fixed member, it is sensitive to tolerance variations, potentially requiring secondary finishing operations.
In view of the foregoing, it is an object of the present invention to provide a latch mechanism which can allow for tolerance variations and secure a seat with minimal chucking and friction problems.
It is another object of the present invention to provide a latch mechanism for a motor vehicle seat having a self-locking feature in response to sudden changes in velocity.
It is yet another related object of the present invention to provide such a latch mechanism that is highly reliable in operation.